A risk-stratified therapy for infants with acute lymphoblastic leukemia: a report from the JPLSG MLL-10 trial.

The prognosis for infants with acute lymphoblastic leukemia (ALL), particularly those with KMT2A gene rearrangement (KMT2A-r), is dismal. Continuous efforts have been made in Japan to investigate the role of hematopoietic stem cell transplantation (HSCT) for infants with KMT2A-r ALL, but improvement in outcome was modest. In the Japanese Pediatric Leukemia/Lymphoma Study Group MLL-10 trial, infants with ALL were stratified into 3 risk groups (low risk [LR], intermediate risk [IR], and high risk [HR]) according to KMT2A status, age, and presence of central nervous system leukemia. Children's Oncology Group AALL0631 modified chemotherapy with the addition of high-dose cytarabine in early intensification was introduced to KMT2A-r patients, and the option of HSCT was restricted to HR patients only. The role of minimal residual disease (MRD) was also evaluated. Ninety eligible infants were stratified into LR (n = 15), IR (n = 19), or HR (n = 56) risk groups. The 3-year event-free survival (EFS) rate for patients with KMT2A-r ALL (IR + HR) was 66.2% (standard error [SE], 5.6%), and for those with germline KMT2A (KMT2A-g) ALL (LR), the 3-year EFS rate was 93.3% (SE, 6.4%). The 3-year EFS rate was 94.4% (SE, 5.4%) for IR patients and 56.6% (SE, 6.8%) for HR patients. In multivariable analysis, female sex and MRD ≥0.01% at the end of early consolidation were significant factors for poor prognosis. Risk stratification and introduction of intensive chemotherapy in this study were effective and were able to eliminate HSCT for a subset of infants with KMT2A-r ALL. Early clearance of MRD seems to have translated into favorable outcomes and should be incorporated into risk stratifications in future trials. This trial was registered at the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) as #UMIN000004801.

Discontinuation of tyrosine kinase inhibitors in pediatric chronic myeloid leukemia.

BACKGROUND: The feasibility of tyrosine kinase inhibitor (TKI) discontinuation in pediatric chronic myeloid leukemia (CML) remains to be fully elucidated. PROCEDURES: TKI was prospectively discontinued in patients who were diagnosed with CML at <20 years of age, treated with TKI for ≥3 years, and sustained molecular response 4.0 (MR4.0) for ≥2 years. Molecular relapse was defined as a single loss of major molecular response (MMR) (BCR-ABL1IS >0.1%). Relapsed patients resumed the same TKI therapy administered before discontinuation. RESULTS: Twenty-two patients with chronic-phase CML were enrolled, and the median ages at diagnosis and at TKI discontinuation were 9 (range: 1-14) years and 16 (5-26) years, respectively. The median follow-up time after TKI discontinuation was 37 months (range: 24-41 months). The median duration of TKI treatment before discontinuation was 100 (42-178) months, and that of MR4.0 was 53.5 (25-148) months. The treatment-free remission (TFR) rate at 12 months was 50.0% (90% confidence interval: 31.7%-65.8%). Eleven patients experienced loss of MMR within 4 months after TKI discontinuation and resumed TKI as originally prescribed. No progression was observed, and all 11 patients regained MR4.0 after TKI resumption. No patient had a withdrawal syndrome. The quality-of-life analysis suggested that successful TFR may improve academic performance in some patients. In patients who discontinued TKI therapy before puberty, the possibility of improvement in growth velocity upon TKI discontinuation was observed. CONCLUSIONS: TKI could be discontinued safely in patients with pediatric CML showing a sustained deep MR.

Acute lymphoblastic leukemia in infants: A quarter century of nationwide efforts in Japan.

Acute lymphoblastic leukemia (ALL) with KMT2A gene rearrangement (KMT2A-r) in infants is a biologically and clinically unique disease and one of the most difficult to cure forms of pediatric leukemia. Multicenter clinical trials have been carried out in Japan since the mid-1990s by introducing allogeneic hematopoietic stem cell transplantation (HSCT) in first remission, which led to a modest improvement in outcome of infants with KMT2A-r ALL. Because of the emerging evidence that HSCT does not benefit every infant with KMT2A-r ALL, the Japanese Pediatric Leukemia/Lymphoma Study Group trial MLL-10 introduced risk stratification using age and presence of central nervous system leukemia, and introduced intensive chemotherapy, including high-dose cytarabine in early consolidation; indication of HSCT was restricted to the patients with high-risk features. The trial resulted in excellent 3-year event-free survival of 66.2% (standard error, 5.6%) and overall survival of 83.9% (standard error, 4.3%) for 75 patients with KMT2A-r ALL recruited between 2011 and 2015. This Japanese experience and the results of the infant ALL trials worldwide suggest the importance of introducing effective therapy in the early phase of therapy, thus clearing minimal residual disease as rapidly as possible. However, further improvement in outcome is unlikely with conventional treatment approaches. Introduction of biology-driven novel agents and/or immunotherapies through international collaboration would be key solutions to overcome the disease.

Virus-triggered secondary hemophagocytic lymphohistiocytosis.

Primary (familial/hereditary) and secondary (non-familial/hereditary) hemophagocytic lymphohistiocytosis (HLH) are hyperinflammatory and hypercytokinemic syndromes. Secondary HLH includes infection- (eg viral/bacterial/fungal/parasitic) and non-infection- (eg collagen disease or malignancy) related diseases. Viral HLH is the major type among all age groups. Secondary viral HLH and primary HLH must be differentiated carefully because primary HLH can be associated with viral infection(s), and the outcome is dismal without a timely diagnosis and hematopoietic stem cell transplantation (HSCT). Epstein-Barr virus (EBV)-related HLH (EBV-HLH) is the most common type of viral HLH in childhood. For non-EBV-HLH, appropriate treatment of viral infection, followed by immunomodulatory agent(s) such as corticosteroids, intravenous immunoglobulin or cyclosporine A, is usually successful; however, recent SARS-CoV-2-related HLH may become life-threatening. EBV-HLH may occur heterogeneously associated with the primary infection, with chronic active EBV infection or with underlying primary HLH. Although immunomodulatory agent(s) are effective in the majority of EBV-HLH cases, management differs from that of non-EBV-HLH because severe and refractory cases may require etoposide-containing HLH-1994/2004 regimens or other experimental agents. The novel agent, emapalumab (an anti-IFN-γ monoclonal antibody) can be used to treat EBV-HLH cases to avoid the risk of secondary malignancy due to etoposide. Finally, HSCT is required for refractory EBV-HLH cases and can also be curative in some other cases.

Human CTL-based functional analysis shows the reliability of a munc13-4 protein expression assay for FHL3 diagnosis.

Familial hemophagocytic lymphohistiocytosis (FHL) is the major form of hereditary hemophagocytic lymphohistiocytosis (HLH); as such, it requires prompt and accurate diagnosis. We previously reported that FHL type 3 (FHL3) can be rapidly screened by detecting munc13-4 expression in platelets using flow cytometry; however, the reliability of the munc13-4 expression assay for FHL3 diagnosis is unclear. Regardless of the type of UNC13D mutation, all reported FHL3 cases examined for the munc13-4 protein showed significantly reduced expression. However, the translated munc13-4 protein of some reportedly disease-causing UNC13D missense variants has not been assessed in terms of expression or function; therefore, their clinical significance remains unclear. The aim of this study was to determine the reliability of a munc13-4 expression assay for screening FHL3. Between 2011 and 2016, 108 HLH patients were screened by this method in our laboratory, and all 15 FHL3 patients were diagnosed accurately. To further elucidate whether munc13-4 expression analysis can reliably identify FHL3 patients harboring missense mutations in UNC13D, we developed an alloantigen-specific cytotoxic T lymphocyte (CTL) line and a CTL line immortalized by Herpesvirus saimiri derived from FHL3 patients. We then performed a comprehensive functional analysis of UNC13D variants. Transient expression of UNC13D complementary DNA constructs in these cell lines enabled us to determine the pathogenicity of the reported UNC13D missense variants according to expression levels of their translated munc13-4 proteins. Taken together with previous findings, the results presented herein show that the munc13-4 protein expression assay is a reliable tool for FHL3 screening.

Renal dysfunction can occur in advanced-stage Duchenne muscular dystrophy.

INTRODUCTION: With improved treatments, patients with Duchenne muscular dystrophy (DMD) can survive far beyond adolescence. However, advanced-stage DMD patients are at risk of developing renal dysfunction. In this study, long-term renal function outcomes and associated risk factors in advanced stage DMD were analyzed. METHODS: Fifty-one patients were classified into three different age groups (<20, 20-29, and ≥30 years of age), and cystatin C (CysC) levels were compared among groups. RESULTS: Median serum CysC levels were 0.74 mg/L, 0.63 mg/L, and 0.76 mg/L in the age groups of <20, 20-29, and ≥30 years, respectively (P = .003). Five of the nine patients in the ≥30 years age group showed elevated serum CysC and decreased cardiac function compared with the other four in the group (P = .014). DISCUSSION: Our results indicate an association between cardiac and renal dysfunction in patients with advanced-stage DMD.

Long-term outcomes of children with extracutaneous juvenile xanthogranulomas in Japan.

BACKGROUND: Juvenile xanthogranuloma (JXG) is the most common non-Langerhans cell histiocytosis in children. The mortality and morbidity of JXG with extracutaneous lesions remain unclear. METHODS: Data of patients aged < 18 years who were diagnosed with JXG between 2001 and 2010 were retrospectively collected through a nationwide survey. RESULTS: Twenty patients (11 male and nine female) had extracutaneous lesions. The median observation time was 10 years (range, 0-17). Six patients presented with symptoms at birth. The median age at diagnosis was 8.5 months (range, 0 month-13 years). Fifteen patients underwent treatment for JXG, including chemotherapy (n = 11), and five did not receive treatment. All patients except one survived; 17 were disease-free and two survived with disease. One newborn-onset patient with liver, spleen, and bone marrow involvement died of the disease. Permanent sequelae included central diabetes insipidus, growth hormone deficiency, and panhypopituitarism detected at diagnosis in three, one, and two patients, respectively. Four patients had visual impairment (optic nerve compression and intraocular invasion in two each), three had epilepsy, one had mental retardation, and one had a skin scar. Eight patients who had intracranial lesions were older at diagnosis, and had a higher frequency of disease-related comorbidities and permanent sequelae than those without intracranial involvement. CONCLUSIONS: Patients with extracutaneous JXG had good outcomes, although those with intracranial lesions had serious permanent sequelae. Effective and safe treatment regimens for patients with intracranial JXG need to be developed.

Early detection of the PAX3-FOXO1 fusion gene in circulating tumor-derived DNA in a case of alveolar rhabdomyosarcoma.

Cell-free DNA (cfDNA), which are small DNA fragments in blood derived from dead cells including tumor cells, could serve as useful biomarkers and provide valuable genetic information about the tumors. cfDNA is now used for the genetic analysis of several types of cancers, as a surrogate for tumor biopsy, designated as "liquid biopsy." Rhabdomyosarcoma (RMS), the most frequent soft tissue tumor in childhood, can arise in any part of the body, and radiological imaging is the only available method for estimating the tumor burden, because no useful specific biological markers are present in the blood. Because tumor volume is one of the determinants of treatment response and outcome, early detection at diagnosis as well as relapse is essential for improving the treatment outcome. A 15-year-old male patient was diagnosed with alveolar RMS of prostate origin with bone marrow invasion. The PAX3-FOXO1 fusion was identified in the tumor cells in the bone marrow. After the diagnosis, cfDNA was serially collected to detect the PAX3-FOXO1 fusion sequence as a tumor marker. cfDNA could be an appropriate source for detecting the fusion gene; assays using cfDNA have proved to be useful for the early detection of tumor progression/recurrence. Additionally, the fusion gene dosage estimated by quantitative polymerase chain reaction reflected the tumor volume during the course of the treatment. We suggest that for fusion gene-positive RMSs, and other soft tissue tumors, the fusion sequence should be used for monitoring the tumor burden in the body to determine the diagnosis and treatment options for the patients.

Confirmed efficacy of etoposide and dexamethasone in HLH treatment: long-term results of the cooperative HLH-2004 study.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening hyperinflammatory syndrome comprising familial/genetic HLH (FHL) and secondary HLH. In the HLH-94 study, with an estimated 5-year probability of survival (pSu) of 54% (95% confidence interval, 48%-60%), systemic therapy included etoposide, dexamethasone, and, from week 9, cyclosporine A (CSA). Hematopoietic stem cell transplantation (HSCT) was indicated in patients with familial/genetic, relapsing, or severe/persistent disease. In HLH-2004, CSA was instead administered upfront, aiming to reduce pre-HSCT mortality and morbidity. From 2004 to 2011, 369 children aged <18 years fulfilled HLH-2004 inclusion criteria (5 of 8 diagnostic criteria, affected siblings, and/or molecular diagnosis in FHL-causative genes). At median follow-up of 5.2 years, 230 of 369 patients (62%) were alive (5-year pSu, 61%; 56%-67%). Five-year pSu in children with (n = 168) and without (n = 201) family history/genetically verified FHL was 59% (52%-67%) and 64% (57%-71%), respectively (familial occurrence [n = 47], 58% [45%-75%]). Comparing with historical data (HLH-94), using HLH-94 inclusion criteria, pre-HSCT mortality was nonsignificantly reduced from 27% to 19% (P = .064 adjusted for age and sex). Time from start of therapy to HSCT was shorter compared with HLH-94 (P =020 adjusted for age and sex) and reported neurological alterations at HSCT were 22% in HLH-94 and 17% in HLH-2004 (using HLH-94 inclusion criteria). Five-year pSu post-HSCT overall was 66% (verified FHL, 70% [63%-78%]). Additional analyses provided specific suggestions on potential pre-HSCT treatment improvements. HLH-2004 confirms that a majority of patients may be rescued by the etoposide/dexamethasone combination but intensification with CSA upfront, adding corticosteroids to intrathecal therapy, and reduced time to HSCT did not improve outcome significantly.

National survey of Japanese patients with mevalonate kinase deficiency reveals distinctive genetic and clinical characteristics.

OBJECTIVES: Mevalonate kinase deficiency (MKD), a rare autosomal recessive autoinflammatory syndrome, is caused by disease-causing variants of the mevalonate kinase (MVK) gene. A national survey was undertaken to investigate clinical and genetic features of MKD patients in Japan. METHODS: The survey identified ten patients with MKD. Clinical information and laboratory data were collected from medical records and by direct interviews with patients, their families, and their attending physicians. Genetic analysis and measurement of MVK activity and urinary excretion of mevalonic acid were performed. RESULTS: None of the 10 patients harbored MVK disease-causing variants that are common in European patients. However, overall symptoms were in line with previous European reports. Continuous fever was observed in half of the patients. Elevated transaminase was observed in four of the 10 patients, two of whom fulfilled the diagnostic criteria for hemophagocytic lymphohistiocytosis. About half of the patients responded to temporary administration of glucocorticoids and NSAIDs; the others required biologics such as anti-IL-1 drugs. CONCLUSION: This is the first national survey of MKD patients in a non-European country. Although clinical symptoms were similar to those reported in Europe, the incidence of continuous fever and elevated transaminase was higher, probably due to differences in disease-causing variants.

Histological characterisation of visceral changes in a patient with type 2 Gaucher disease treated with enzyme replacement therapy.

Gaucher disease is a lysosomal storage disease caused by deficiency of glucocerebrosidase and accumulation of glucocerebroside. Three major sub-types have been described, type 2 is an acute neurological form that exhibits serious general symptoms and poor prognosis, compared with the other types. This case was a girl diagnosed with type 2 Gaucher disease at 12months of age who presented with poor weight gain from infancy, stridor, hypertonia, hepatosplenomegaly, trismus and an eye movement disorder. Enzyme replacement therapy (ERT) was administered, but she had frequent myoclonus and developmental regression. She needed artificial ventilation because of respiratory failure. She died at 11years of age. An autopsy demonstrated infiltrating CD68-positive large cells containing abundant lipids in alveoli, while in the liver, kidney and bone marrow CD68-positive cells were small and round. In the bone marrow, myelodysplastic changes were present without Gaucher cells. The infiltration of Gaucher cells in alveoli was marked, suggesting that ERT was relatively ineffective in pulmonary involvement, particularly intra-alveolar. Additional treatments are necessary to improve the neurological and pulmonary prognosis of type 2Gaucher disease.

Manifestation of recessive combined D-2-, L-2-hydroxyglutaric aciduria in combination with 22q11.2 deletion syndrome.

22q11.2 deletion syndrome is one of the most common human microdeletion syndromes. The clinical phenotype of 22q11.2 deletion syndrome is variable, ranging from mild to life-threatening symptoms, depending mainly on the extent of the deleted region. Brain malformations described in association with 22q11.2 deletion syndrome include polymicrogyria, cerebellar hypoplasia, megacisterna magna, and agenesis of the corpus callosum (ACC), although these are rare. We report here for the first time a patient who manifested combined D-2- and L-2-hydroxyglutaric aciduria as a result of a hemizygous mutation in SLC25A1 in combination with 22q11.2 deletion. The girl was diagnosed to have ACC shortly after birth and a deletion of 22q11.2 was identified by genetic analysis. Although the patient showed cardiac anomalies, which is one of the typical symptoms of 22q11.2 deletion syndrome, her rather severe phenotype and atypical face prompted us to search for additional pathogenic mutations. Three genes present in the deleted 22q11.2 region, SLC25A1, TUBA8, and SNAP29, which have been reported to be associated with brain malformation, were analyzed for the presence of pathogenic mutations. A frameshift mutation, c.18_24dup (p.Ala9Profs*82), was identified in the first exon of the remaining SLC25A1 allele, resulting in the complete loss of normal SLC25A1 function in the patient's cells. Our results support the notion that the existence of another genetic abnormality involving the retained allele on 22q11.2 should be considered when atypical or rare phenotypes are observed.

Sequential use of second-generation tyrosine kinase inhibitors following imatinib therapy in pediatric chronic myeloid leukemia: A report from the Japanese Pediatric Leukemia/Lymphoma Study Group.

BACKGROUND: The details of the sequential use of imatinib for first-line treatment followed by second-generation tyrosine kinase inhibitors (2G-TKIs) for pediatric chronic myeloid leukemia (CML) are still unknown. This study analyzed clinical responses and adverse effects of the use of 2G-TKIs following imatinib in pediatric chronic phase (CP)-CML. PROCEDURES: The Japanese Pediatric Leukemia/Lymphoma Study Group conducted a retrospective study of patients with newly diagnosed CML from 1996 to 2011. A total of 152 cases that received imatinib as first-line therapy were analyzed. RESULTS: Excluding 46 cases treated with hematopoietic stem cell transplantation before nilotinib and dasatinib became available, 31 of 106 patients changed to 2G-TKIs. The primary reason for changing from imatinib was poor response, followed by intolerance, with the main reason for the latter being musculoskeletal events. Switches from imatinib to 2G-TKIs with intolerance occurred significantly earlier than switches with poor response. Sixteen and 15 patients were treated with nilotinib and dasatinib, respectively, following imatinib therapy. After switching to 2G-TKIs, the response status improved in 63% of evaluable patients. The adverse effect profiles of nilotinib and dasatinib tended to be different, with hyperbilirubinemia observed in 33% of nilotinib-treated patients, but in none of the cases with dasatinib. CONCLUSION: This retrospective study represents the first series of children and adolescents in whom sequential use of imatinib followed by 2G-TKIs was reported. These data provide useful insights into the selection of 2G-TKIs as first-line treatment for children and adolescents with CP-CML.

What information can change the attitude of teachers toward the human papillomavirus vaccine?

AIM: We conducted a self-administered survey on the perception of teachers toward human papillomavirus (HPV) vaccine to determine the ways to increase their willingness to encourage its use. METHODS: Answers were obtained both prior to and after having the teachers read five brief information articles: (i) cervical cancer knowledge, (ii) vaccine knowledge, (iii) result of a survey in Nagoya, (iv) news report of the World Health Organization statement and (v) articles written by Dr Muranaka, a journalist. RESULTS: Most of the respondents (180/247) did not know about the natural history of cervical cancer. Only 36% knew that HPV is the cause of cervical cancer, although 63% knew that HPV vaccine would prevent cervical cancer. Few respondents had knowledge regarding adverse events following immunization and the survey results from Nagoya. Among those who were initially negative for the HPV vaccine, only 43% revealed that they fully understood its safety and only 29% reversed their opinion to recommend vaccination to their daughters and/or students, even after reading our informational material. The most useful information for changing their attitudes was to increase their understanding of vaccines and informing them about Nagoya city survey results. They mostly wanted a proof of the preventive effects of the vaccine on cervical cancer in Japan. CONCLUSION: Gynecologists and pediatricians must proactively communicate accurate scientific information to the government and the media to spread awareness among people in Japan. Also, we must try to demonstrate the capabilities of this vaccine to prevent cervical cancer and/or its precancerous lesions.

Exon skipping in CYBB mRNA and skewed inactivation of X chromosome cause late-onset chronic granulomatous disease.

Chronic granulomatous disease (CGD) is a hereditary immunodeficiency syndrome caused by a defect in the NADPH oxidase complex, which is essential for bactericidal function of phagocytes. Approximately 70% of patients with CGD have a mutation in the CYBB gene on the X chromosome, resulting in defective expression of gp91phox, one of the membrane-bound subunits of NADPH oxidase. Although most patients with X-linked CGD are males, owing to transmission of this disease as an X-linked recessive trait, there are female patients with X-linked CGD. Here, we report the case of a teenage girl with X-linked CGD associated with a heterozygous mutation in exon 5 of the CYBB gene (c.389G > C; R130P), which causes skipping of exon 5, resulting in a premature stop codon in exon 6 of CYBB. Accurate pro-mRNA splicing for mature mRNA formation is regulated by several splicing mechanisms that are essential for appropriate recognition of exonic sequences. The c.389G > C mutation disrupts exonic-splicing regulator sequences, thereby resulting in the aberrant skipping of exon 5 in the CYBB transcript of the patient. The patient showed an extremely skewed (≥96%) X inactivation pattern of the HUMARA locus; this inactivation is thought to be responsible for the development of CGD not only in neutrophils but also in monocytic, T-cell, and B-cell lineages and in CD34-positive immature hematopoietic cells. Our case and other reports indicate that the onset of X-linked CGD in female patients tends to occur later in life, and that the symptoms tend to be milder as compared to male patients.

Prolonged adrenal insufficiency after high-dose glucocorticoid in infants with leukemia.

Although outcomes for infant leukemia have improved recently, transient adrenal insufficiency is commonly observed during treatment, especially after glucocorticoid administration. We identified three infants with acute leukemia who suffered from prolonged adrenal insufficiency requiring long-term (from 15 to 66 months) hydrocortisone replacement. All infants showed life-threatening symptoms associated with adrenal crisis after viral infections or other stress. Severe and prolonged damage of hypothalamo-pituitary-adrenal (HPA) axis is likely to occur in early infants with leukemia, therefore routine tolerance testing to evaluate HPA axis and hydrocortisone replacement therapy are recommended for infants with leukemia to avoid life-threatening complications caused by adrenal crisis.

Usefulness of positron emission tomography-CT for diagnosis of primary bone marrow lymphoma in children.

Primary bone marrow lymphoma (PBML) is hard to diagnose in children, due to the difficult identification of malignant cells in bone marrow. The first case, a 5-year-old boy, showed knee swelling with an intermittent fever. The second case, a 12-year-old girl, showed fever of unknown origin without lymphadenopathy or hepatosplenomegaly. In both cases, the diagnosis was not confirmed despite the repeated bone marrow aspirations. Finally, bone marrow aspiration and biopsy at the positive site by positron emission tomography (PET)-CT contributed to definitive diagnosis of PBML. The PET-CT is useful for the accurate diagnosis of PBML in children with non-specific symptoms.

Characteristics and outcome of intractable vasculitis syndrome in children: Nation-wide survey in Japan.

OBJECTIVE: Primary systemic vasculitis (PSV) is a rare disorder in children and difficult to distinguish from other diseases. However, appropriate diagnosis and prompt treatment will affect on the morbidity and mortality of intractable PSV. In this study, we conducted a nationwide survey in Japan, to clarify epidemiology and clinical outcome of PSV. METHODS: We had sent survey questionnaires to most of the Japanese institutions that employed pediatricians, requesting the number of patients with refractory PSV who were diagnosed and treated between 2007 and 2011. Respondents were asked to provide detailed information on the clinical and laboratory features of each case they had managed. Those with Kawasaki disease or Henoch-Shönlein purpura vasculitis (IgA vasculitis) were excluded. RESULTS: Of all the institutions surveyed, 1123 (37.3%) patients responded, finally, total of 49 patients with intractable PSV, defined by those with resistant to treatment and steroid-dependent, or with any complication associated with prognosis, were selected. The diagnosis was Takayasu arteritis in 31, polyarteritis nodosa in 11, granulomatosis with polyangitis in 2, microscopic polyangitis in 1, and ANCA negative microscopic polyangitis in 1. In those with Takayasu arteritis, 67% were treated with an immunosuppressive agent, 22% with biological modifiers, and 16% with surgical procedures. In other types of disease, 88% of the patients were treated with an immunosuppressive agent, and 12% with biological modifiers. Two with Takayasu arteritis died being terminally ill. CONCLUSION: This nationwide survey establishes the heterogeneous characteristics of PSV in children. Although questionnaire-based, the results of our analysis should be useful in planning prospective studies to identify the most effective therapy for each subtype of multifaceted disease.

Multicolor Flow Cytometry for the Diagnosis of Primary Immunodeficiency Diseases.

PURPOSE: Primary immunodeficiency diseases (PIDDs) are rare inherited diseases that impair the human immune system. We established a multicolor flow cytometric assay to comprehensively evaluate the immune status and immunological characteristics of patients with PIDDs. METHODS: Fifty-nine normal controls and 75 patients with PIDDs, including X-linked severe combined immunodeficiency (X-SCID), X-linked agammaglobulinemia (XLA), X-linked hyper IgM syndrome (X-HIGM), ataxia telangiectasia (AT), Wiskott-Aldrich syndrome (WAS), hyper IgE syndrome (HIES), and chronic mucocutaneous candidiasis disease (CMCD), were enrolled in this study. Immunophenotyes were evaluated by multicolor flow cytometry using seven different panels that allowed the detection of major leukocyte populations in peripheral blood. RESULTS: Multicolor flow cytometry revealed distinct leukocyte populations and immunological features of patients with X-SCID, XLA, X-HIGM, AT, WAS, HIES, and CMCD. CONCLUSIONS: Immunophenotyping by multicolor flow cytometry is useful to evaluate immune status and contributes to the diagnosis and management of patients with PIDDs.

A CD57+ CTL Degranulation Assay Effectively Identifies Familial Hemophagocytic Lymphohistiocytosis Type 3 Patients.

PURPOSE: Familial hemophagocytic lymphohistiocytosis type 3 (FHL3) is a genetic disorder that results in immune dysregulation. It requires prompt and accurate diagnosis. A natural killer (NK) cell degranulation assay is often used to screen for FHL3 patients. However, we recently encountered two cases of late-onset FHL3 carrying novel UNC13D missense mutations: in these cases, the degranulation assays using freshly isolated and interleukin (IL)-2-activated NK cells yielded contradictory results. Since the defective degranulation of CD57+ cytotoxic T lymphocytes (CTLs) in these cases was helpful for making the diagnosis, we assessed whether the CD57+ CTL degranulation assay more effectively identified FHL3 patients than the NK cell assays. METHODS: Forty additional patients with hemophagocytic lymphohistiocytosis were prospectively screened for FHL3 by measuring the perforin expression in NK cells and the expression of Munc13-4, syntaxin-11, and Munc18-2 in platelets and by performing NK cell and CTL degranulation assays. The results were confirmed by genetic analysis. RESULTS: The freshly isolated NK cell degranulation assay detected FHL3 patients with high sensitivity (100%) but low specificity (71%). The IL-2-stimulated NK cell assay had improved specificity, but 3 out of the 31 non-FHL3 patients still showed degranulation below the threshold level. The CD57+ CTL degranulation assay identified FHL3 patients with high sensitivity and specificity (both 100%). CONCLUSIONS: The CD57+ CTL degranulation assay more effectively identified FHL3 patients than the NK cell-based assays.